1. Field of the Invention
This invention relates to a treating tool useable with an endoscope which is not damaged or broken in case an excess operating force is applied.
2. Related Art Statement
Recently, medical endoscopes have become widely used whereby an organ or the like within a body cavity of a patient can be observed by inserting the endoscope into the body cavity. A treatment can be made using a treating tool by inserting an elongated insertable part of the tool through a treating tool channel of the endoscope as required. Also, in the industrial field, industrial endoscopes are being widely used whereby the interior of a boiler, turbine, engine or chemical plant can be observed.
Various different treating tools can be used as accessories together with or independently of the above mentioned endoscope such as a biopsic forceps or a holding forceps. A biopsic forceps is shown, for example, in the gazette of Japanese utility model application laid open No. 193811/1982. FIG. 11 is an elevation showing this biopsic forceps. A biopsic forceps 1 is formed of a sheath 2, a treating part 3 provided adjacent the tip part of this sheath and an operating part 4 provided in the base end part of the sheath 2. The sheath 2 consists of a pipe 10 through which an operating shaft 5 as shown in FIG. 12 is inserted. A pair of biopsic cups 6 and 7 are fitted by brazing or the like to the tip part of this operating shaft 5. These biopsic cups 6 and 7 are formed of a pair of holding pieces 6a and 7a which are resilient tending to separate and open them to be in the form of V. Cup-like cutting blades 6b and 7b are formed at the open ends of these holding pieces 6a and 7a. A male screw part 5a is formed in the rear end part of the operating shaft 5.
A base member 8 having an engaging part 8a on the sides is fixed to the rear end part of the sheath 2. A pair of handles 11 and 12 having finger loops 11a and 12a and being pivoted at their center portions 13 with a pivoting pin 14 without intersecting with each other are provided as the operating part 4. A U-like groove 15 is formed in the tip part of the front side handle 11 and is engaged with the engaging part 8a of the base member 8. An inserting hole through which the operation shaft 5 is inserted in the rear end part is formed in the tip part of the rear side handle 12. The operating shaft 5 is inserted in the rear end part through this inserting hole and projects on the rear side of the handle 12. A stopper screw 17 for stopping the escape of this operating shaft 5 is screwed to a male screw part 5a of the operating shaft 5.
Further, a screw hole intersecting at right angles with the inserting hole is provided in the tip part of the handle 12. A fixing screw 19 fixing the operating shaft 5 is screwed in this screw hole so that the forward and rearward position of the operating shaft 5 may be adjustable.
In such formation, when the finger loops 11a and 12a of the handles 11 and 12 are operated in the opening direction (that is, apart from each other), the tip parts of the handles 11 and 12 will move in the closing direction (that is, towards each other) and the pipe 10 will move rearward with respect to the operating shaft 5. Then, the holding pieces 6a and 7a will project out of the pipe 10 and will open in the form of V. When the finger loops 11a and 12a of the handles 11 and 12 are operated in the closing direction, the holding pieces 6a and 7a will be retracted into pipe 10 and the cutting blades 6b and 7b will come together so that a sample of living body tissue may be collected.
Now, in using the above described biopsic forceps 1, in such case that the tissue to be collected is hard, if an excess force is applied to the handles 11 and 12, the biopsic cups 6 and 7 of the treating part 3 are likely to be broken.
A technique wherein an operating mechanism is provided with a flexible coil so that an excess force applied to the operating part may be absorbed by the flexible coil is disclosed, for example, in the gazette of Japanese utility model laid open No. 40964/1982 or in the West German patent application No. 2735706.
However, in the above mentioned related technique, all of the excess force will not be absorbed by the flexible coil and a part of the excess force will be applied to the operating wire and biopsic cups and therefore the biopsic cups and others will not be able to be perfectly prevented from being broken.